Drawing the ethical line

Here's the situation. I met an acquaintance during our IF struggle. She went through the adoption process first and when we started thinking about it, she has been a very helpful guide to get the lay of the land. I truly appreciate this.

So what's the problem?

I've mentioned before (and anyone who knows anything about adoption) that there are ethical decisions to make along your adoption journey. There is not necessarily a "right" decision for all, but we each need to decide what we feel comfortable with and what we think crosses the line into more of a transaction. The problem is that this friend used an agency that we think crossed that line. I don't judge her for using them, but still we don't want to do the same thing. The problem is that she keeps encouraging us to use this agency, raving about them. At first I didn't say anything but just said we are looking at a number of agencies. But now she keeps bringing it up and I don't know how to tell her we don't feel comfortable using that agency without saying that we think their model crosses a line for us.